In general, a load test of a pile is executed for the purpose of obtaining a data for determining the bearing capacity, by applying a load to the pile head, and measuring a relation between the load to the pile and a displacement.
As this kind of pile load test, there have been known a static load test in which a static load is applied to a pile head step by step for a long time, and a relation between the load and a pile settlement amount is determined, and a dynamic load test, in which a heavy weight is dropped on the pile head, and a settlement amount of the pile due to an impact is measured. Further, there has been recently executed a pseudostatic load test, in which a soft cushion is put on the pile head, and the heavy load is dropped thereon.
Reference is made to a patent document, Japanese Unexamined Patent Publication No. 2002-303570, and a non-patent document, Japanese Geotechnical Society Standard, Pile Vertical Load Testing Method and Comments Thereof, Sixth Edition Pages 185 to 190 (issued by Japanese Geotechnical Society).